1994 BMW 325i air temperature

NOTE-

"
On
carswith
OBD
ti,
specialized
OBD
11
scan
tool
equipment
must
be
used
to
access
the
DTCs,
either
using
the
BMW
special
tool
ora
`generic"
OBD
11
scan
tool
.
See
130
Fuel
Injection
.

"
The
08D
11
fault
memory
(including
an
iiluminated
Check
Engine
light)
can
only
be
reset
using
the
spe-
cial
scan
tool
.
Removing
the
connector
from
the
ECM
or
disconnecting
the
battery
will
not
erase
the
fault
memory
.

Table
d
.
OBD
1
Fault
(Blink)
Codes

(1992-1995
modeis
only)

Graphic
representation
of
flashing
Check
Engine
light
fault
code
:
1221
5
Seconds
.
:-



2
.5~-

--05--

Fault
code
and
meaning



1
Corrective
action

Code
1216
:
Throttle
potentiometer

Code
1218
:
Output
stage,
group#1
(DME
3
.3
.ionly)

Code
1219
:
Output
stage,
group
#2
(DME
3
.3.1
only)

Code
1221
:
Oxygen
sensor
#1

Code
1224
:
Air
temperature
sensor
(NTC)

Code
1226
:
Knock
sensor
#2
(DME
3
.3
.1
only)

130

ENGINE-GENERAL
100-
9

2
.5
seconds,
then
go
off
for
2
.5
seconds
.
At
thispoint,
the
fault
codes
will
begin
to
flash
.
See
Table
d
.

If
more
than
one
fault
has
been
detected,
eachcode
will
be
separated
by
a2
.5
second
pause
.
When
al¡
fault
codes
havebeen
displayed,
there
will
be0
.5
second
flash
and
thenthe
light
will
remain
off
.
To
read
the
codes
again,
turn
the
key
off
and
then
on
again
.
Depress
theaccelerator
pedal
to
the
floor
five
times
quickly
(within
5
seconds)
.
The
codes
will
begin
to
repeat
.

On
cars
with
OBD
I,
fault
codes
can
be
read
by
turning
the



To
erase
the
fault
code
memory,
first
make
sure
the
fault

ignition
key
on
and
fully
depressing
theaccelerator
pedal
to



code
1000
(short
blink
and
then
light
goes
out
for
long
period)

the
floor
five
times
within
five
seconds
.
TheCheck
Engine



is
present,
then
depress
the
throttle
fully
for
at
least
10
sec-

light
will
then
remain
on
for
five
seconds,
blink
off,
come
on
for



onds
.
Read
the
fault
codes
as
described
earlier
and
check
for
the
1444
code
(no
faults
stored)
.

-,--------------
Check
Engine
light
on

Check
Engine
light
off

Code
1211
:
DM
E
Control
Module



DME
control
module
may
be
faulty
.
This
code
appears
if
the
control
module
fails
the
self
test
.
Check
inputsto
control
module
.
Repair
Group
130

Code
1215
:
Mass
air
flow
sensor



Check
air
flow
or
mass
air
flow
sensor
and
wiring
to
sensor
.
Repair
Group
130

Test
throttle
potentiometer
resistance
and
wiring
.
Repair
Group
130

Test
DME
control
module
input/outputs
.
Repair
Group
130

Test
DME
control
module
input/outputs
.
Repair
Group
130

Check
sensor
output
signal
to
DME
control
module
.
Repair
Group

Code
1222
:
Oxygen
sensor
lean/rich
control
stop



Check
for
intake
air
leaks
or
reasons
forrich
míxture
.
See
Driveabil-
ity
Troubleshooting
given
earlier
in
this
repair
group

Code
1223
:
Coolant
temperaturesensor
(NTC)



1
Test
coolant
temperature
sensor
.
Repair
Group
130

Test
intake
air
temperature
sensor
.
Repair
Group
130

Code
1225
:
Knock
sensor#1
(DME
3
.3
.1
only)



1
Check
knocksensorand
sensor
wiring
.
Repair
Group
120

Check
knocksensor
and
sensor
wiring
.
Repair
Group
120

Code
1231
:
Batteryvoltage
monitor



Test
battery
voltage
and
battery
check
charging
system
and
starter
.
Repair
Group
121

Code
1234
:
Speedometer
"A"signal
(DME
3
.3
.1
only)



Check
wiring
between
instrument
cluster
and
DME
control
module
.
Electrical
Wiring
Diagrams

Code
1237
:
A/C
compressor
cutoff
(DME
3
.3
.1
only)



Test
DME
control
module
inputs/outputs
from
A/C
system
.
Repair
Group
130

Code
1242
:
A/C
compressor
signal
(DME
3
.3.1
only)



Test
DME
control
module
inputs/outputs
from
A/C
system
.
Repair
Group
130

DRIVEABILITY
TROLIBLESHOOTING

100-
1
2
ENGINE-GENERAL

NOTE-

The
oxygen
sensor
signal
is
ignored
until
the
engine
reachesa
specified
minimum
temperature
.
Therefore,



The
primary
input
usedby
the
fuel
injection
system
to
deter-

when
troubleshooting
cold
engine
driveability
prob-



mine
how
much
fuel
should
be
delivered
is
the
signal
from
the

lems,
the
oxygensensor
canbe
ruled
out
asa
possible



mass
air
flow
sensor
in
the
intake
air
ductwork
.

cause
.

As
the
oxygen
sensor
ages,
its
ability
to
react
quickly
to

changing
conditions
deteriorates,
and
it
may
eventually
cease

to
produce
any
signal
at
all
.
To
check
the
operation
of
the
oxy-

gen
sensor,
see
130
Fuel
Injection
:

NOTE-

On
1996
and
latercars,
OBD
11
enhanced
emission
standards
require
the
engine
control
module
(ECM)
to
monitor
the
oxygen
content
in
the
exhaust
both
before
and
after
the
catalytic
converter
.
Thisallows
for
tighter
control
of
the
tail
pipe
emissions
and
also
allowsthe
ECM
to
diagnose
converter
problems
.
If
the
DME
de-
tects
that
catalytic
converter
or
oxygensensor
efficien-
cyhas
degraded
pasta
certain
pre-programmed
limit,
it
will
turn
on
the
Check
Engine
light,
and
store
a
diag-
nostic
trouble
code
(DTC)
in
the
ECM
.

DRIVEABILITY
TROUBLESHOOTING

Catalytic

B9506

Air
Flow
Measurement
and
Vacuum
Leaks

Because
proper
fuel
metering
depends
on
accurate
mea-

surement
of
the
incoming
air,
any
unmeasured
air
that
enters

the
engine
downstream
of
the
mass
air
flow
sensor
will
cause

a
lean
air-fuel
mixture
and
possibly
affectdriveability
.

NOTE-

Fig
.
10
.
Regulating
oxygen
sensor
measures
oxygen
content
of
ex-



gattery
Voltage
hausY
gas
as
indicator
of
.¡_fi
.1
ratio
and
"-k,
.

E-
effi-
ciency
.
Monitoríng
oxygen
sensor
(not
shown)
monitors

If
a
large
air
leak
is
causing
driveability
problems,
the
Check
Engine
light
will
usually
be
illuminated
and
a
fault
will
be
stored
in
the
fault
code
memory
.
See
On
Board
Diagnostics
(OBD)
.

There
are
many
places
for
unmeasured
air
to
enter
theen-

gine
.
First,
inspect
all
hoses,
fittings,
ducts,
seals,
and
gaskets

in
the
intake
air
tract
for
cracks
or
looseness
.
It
may
be
neces-

sary
to
remove
parts
that
cannot
be
fully
checked
in
their
in-

stalled
positions
.
Also
make
sure
all
of
the
intake
manifold
and

throttle
body
mounting
nuts
are
tight
.

In
addition
to
air
leaks,
air
restrictions
can
also
cause
drive-

ability
problems
.
Remove
the
air
filter
and
hold
it
up
to
a
strong

light
source
.
If
the
filter
does
not
pass
light,
it
is
restricted
and

should
be
replaced
.
Also,
remove
the
intake
air
ductwork
and

check
for
oily
deposits
at
the
throttle
plate
.
Buildup
in
this
area

can
cause
an
erratic
idle
.
Clean
away
any
deposits
using
a

cloth
wetted
withcarburetor
cleaner
and
reinstall
the
ductwork
.

CAUTION-

Do
not
spray
carburetor
cleaner
directly
in
the
throt-
tle
anea
.
Spraying
cleaner
may
force
it
into
the
throt-
tle
position
switch
or
sensor
and
cause
damage
.

catalytic
converter
operation
.



All
of
the
electrical
components
in
the
fuelinjection
and
igni-
tion
systems
require
a
minimum
voltage
to
operate
properly
.

When
troubleshooting
engine
driveability
problems,
one
of
Replacement
of
oxygensensors
at
the
specified
intenrals
en-



the
first
checks
should
be
to
make
sure
the
battery
is
fully
sures
that
the
engine
and
emission
control
system
wili
continue



charged
and
capable
of
delivering
allits
power
to
the
electricalto
operate
as
designed
.
As
the
oxygen
sensor
ages,
its
ability
to



system
.
react
quickly
to
changing
conditions
deteriorates,
and
it
may
eventually
cease
to
produceany
signal
at
all
.



To
make
a
quick
check
of
battery
charge,
measure
the
volt-
age
across
the
battery
terminals
with
all
cables
attached
and
As
the
oxygen
sensor
ages,
its
ability
to
react
quickly
to



the
ignition
off
.
A
fully
charged
battery
will
measure
12
.6
volts
changing
conditions
deteriorates,
and
it
may
eventually
cease



or
slightly
more,
compared
to
12
.15
volts
for
a
battery
with
a
to
produce
any
signal
at
all
.
To
check
theoperation
of
the
oxy-



25%
charge
.
gen
sensor,
see130
Fuel
Injection
.

Even
a
fully
charged
battery
cannot
deliver
power
unless
it

is
properly
connected
to
the
electrical
system
.
Check
the
bat-
tery
terminals
for
corrosion
and
loosecableconnections
.
If
the
battery
does
not
maintain
the
proper
voltage,
the
charging
system
may
be
atfault
.
See
121
Battery,
Starter,
Alternator
.

113-4



CYLINDER
HEAD
REMOVAL
AND
INSTALLATION

20
.
Disconnect
main
engine
wiring
harness
connector
.
La-

bel
and
disconnect
harness
connectors
for
crankshaft

and
camshaft
sensors
.
See
Fig
.
8
.

0012504

Fig
..
Crankcase
vent
valve
(A),
camshaft
and
crankshaft
sensor
harness
connectors
(B),
locating
bushings
(C),
main
engine
wiring
harnessconnector
(D)
.
M44
engine
shown
.

NOTE-

Early
engines
do
not
havea
maín
disconnect
at
the
lower
intake
manifold
harness
.
lf
necessary,
remove
the
cable
ducting
bolts
and
set
harness
ducting
aside
.

21
.
Remové
lower
section
of
intake
manifold
.

"
Remove
Y
shaped
supportbracket
from
underside
of
manifold
.
(See
Fig
.
6
.)
"
Unbolt
support
brackets
from
alternator
and
starter
.
"
Remove
nuts
holding
manifold
to
cylinder
head
and
pull
manifold
back
until
harness
connectors
for
oil

pressure
switch
and
coolant
temperature
sensorare

accessible
.
Label
and
disconnect
connectors,
then
re-

move
manifold
and
set
aside
.

Timing
chains,
uncoupling



26
.
Lock
crankshaft
in
TDC
position
by
insertíng
BMW
spe-

22
.
On
M42
engines,
remove
thermostat
housing
from
up-



cial
tool
no
.
11
2
300
through
bore
and
into
hole
infly-

per
timing
chaincover
.



wheel
or
driveplate
.
See
Fig
.
11
.

23
.
On
late
M44
engines
(January
1997
and
later),
remove



NOTE-
secondary
air
injection
check-valve
from
front
of
engine



"
If
necessary,
remove
plug
from
locating
bore
in
lower
and
lay
aside
.



edge
of
bell
housing
to
insert
locking
tool
.

24
.
Remove
cylinder
identification
sensor
from
upper
tim-
ing
chaincover
.
Remove
upper
timing
chaincover
.
See
Fig
.
9
.

25
.
Set
engine
to
approximate
TDC
by
rotating
in
normal
operating
direction
until
camshaft
lobes
at
cylinder
no
.
1
are
facing
each
other
.
See
Fig
.
10
.

CYLINDER
HEAD,
4-CYLINDER

Fig
.
9
.



Upper
timing
chain
cover
bolts
(arrows)
.
Remove
secondary
air
injection
check
valve
fromhose
(A)
on
M44
engine
.
Re-
move
cylinder
identification
sensor
from
chaincover
(B)
.

0011998

Fig
.
10
.
Engine
set
to
approximate
TDC
.
Cylinder
no
.
1
camshaft
lobes
face
in
and
arrows
on
sprockets
poínt
up
(arrows)
.

"
Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotate
the
crankshaft
.

27
.
Lock
camshafts
at
TDC
by
mounting
BMW
specíal
tool
no
.
113
240
over
square
ends
of
camshafts
.
See
Fig
.
12
.

NOTE-

Check
that
tool
is
squarely
seated
on
cylinder
head
gasket
surface
.
If
necessary,
rotate
camshafts
slightly
using
an
open-end
wrench
at
hex
oncamshafts
.

117-
1
4



CAMSHAFT
TIMING
CHAIN

22
.
Installation
of
remaining
parts
is
reverse
of
removal,



When
theengine
is
running,
the
piston
housing
is
supplied

noting
the
following
:



with
pressurized
engine
oil
.
At
idie,
the
solenoid
isin
the
off

"
When
installing
thermostat,
make
sure
arrow
or
vent



position
(de-energized)
and
valve
timing
is
maintained
in
the

hole
faces
up,
if
applicable
.



normal
position
:
When
the
solenoid
is
energized,
the
gear
cup

"
Refill
cooling
systemas
described
in
170
Radiator



piston
moves
forward
to
advance
the
camshaftby
a
maximum

and
Coming
System
.



of
12
.5
.

"
Install
oil
pan
as
described
in
119
Lubrication
Sys-

tem
.
"
Fill
engine
with
oil
and
install
a
new
oil
filter
as
de-

scribed
in
020
Maintenance
Program
.

"
Insta¡¡
ground
wires
at
cylinder
head
cover
mounting

studs
and
at
front
of
cylinder
head
and
thermostat

housing,
where
applicable
.



VANOS
system
operation,
testing

Tightening
Torques



There
are3
special
tools
required
to
check
VANOS
opera-

"
Coolant
drain
plugto
cylinder
block
.
.
25
Nm
(18
ft-Ib)



tion
;
an
electricaltest
lead
(BMW
special
tool
no
.
12
6
410),
an

"
Radiator
cooling
fan
to
coolant
pump
.
40
Nm
(30
ft-Ib)



air
line
fitting
(BMW
special
tool
no
.
11
3
450),
and
a
crank-

"
Radiator
drain
screw
to
radiator
...
.
2
.5
Nm
(22
in-Ib)



shaft
TDC
locking
tool
(BMW
special
tool
no
.
112
300)
.

"
Upper
timing
chaincover
to
cylinder
head



The
test
leal
is
used
to
power
the
solenoid,
simulating
the
M6
nut
...
.....
.............
..
.
10
Nm
(89
in-lb)



ground
signal
from
the
DME
control
unit
.
The
air
line
fitting
M8
bolt
.....
....
.
.
.............
22
Nm
(17
ft-Ib)



takes
the
place
of
the
oil
supply
line
fitting
to
simulate
oil
Ares-
"
VANOS
control
unit
to
cylinder
head



sure
.
The
locking
tool
positions
and
locks
the
crankshaft
at

M6
nut
.........
..
..
.
..........
10
Nm
(89
in-lb)



TDC,
cylinder
no
.
l.
M8
bolt
........
...
.............
22
Nm
(17
ft-Ib)

"
VANOS
oil
supply
pipe
to
VANOS
control
unit



1
.
Remove
alternator
cooling
air
duct
.

banjo
bolt
.......
..
..
.
..........
32
Nm
(24
ft-Ib)

VANOS
(VARIABLE
VALVE
TIMING)



3
.
Remove
top
plastic
enginecovers
.
Disconnect
ignition

coil
harness
connectors
fromcofs
.
Remove
ignition

1993
and
later
6-cylinder
engines
are
equipped
with
a
vari-



coils
.

able
valve
timing
system
called
VANOS
.
This
system
is
con-

trolled
by
the
engine
management
system
and
dynamically



4
.
Remove
cylinder
head
cover
mounting
bolts
and
re-

adjusts
intake
camshaft
timing
based
on
engine
load,
engine



move
cylinder
head
cover
.
Unclip
andremove
oil
baffle

speed
and
engine
temperature
.



cover
from
above
intake
camshaft
.
See
113
Cylinder

Head
Removal
and
installation
.

The
main
components
of
the
VANOS
system
are
the
control

unit
with
piston
housing
and
integral
spool
valve,
and
the
mod-

ified
intake
camshaft
.
See
Fig
.
35
.

VANOS
(VARIABLE
VA
LVE
TIMING)

Fig
.
35
.
VANOS
control
unit
with
modified
intake
camshaft
.

B11001

WARNING
-

Special
BMW
service
tools
are
required
to
check
and
repair
the
VANOS
System
.
Read
theproce-

dures
through
before
beginning
the
job
.

2
.
Disconnect
crankcase
ventilation
hose
fitting
from
cyl-

inder
head
cover
.

NOTE-

Note
the
arrangement
of
the
cylinder
head
cover
bolt
insulators
and
gaskets
during
removal
.

5
.
Set
engine
to
approximate
TDC
by
rotating
in
normal

operating
direction
until
camshaft
lobes
at
cylinder
no
.

1
are
facing
each
other
.
See
Fig
.
20
.

6
.
Set
engine
to
TDC
by
aligning
"0/T"
mark
(0°TDC)on

front
vibration
damper
withcast
boss
on
lower
timing
chain
cover
.
See
Fig
.
21
.

7
.
Lock
crankshaft
in
position
by
inserting
BMW
special

tool
no
.
11
2
300
through
transmission
bellhousing
and

into
hole
in
flywheelor
driveplate
.
See
Fig
.
36
.

NOTE-

Confirm
that
the
locking
tool
has
been
correctly
in-
stalled
by
trying
to
rotatethe
crankshaft
.

119-2



LUBRICATION
SYSTEM

NOTE-
Component
Location



If
the
light
does
not
go
out,
thewiring
to
theswitch
is"
Oil
pressure
switch



most
likely
grounded
somewhere
between
the
switch

all
engines
.......
...
.
..
......
ora
oil
filter
housing



terminal
and
the
warning
light
.
Sea
Electrical
Wiring

Diagrams
atrearof
manual
for
electrical
schematics
.

CAUTION-

Some
oil
may
drain
out
as
the
oil
pressure
switch
is
removed
.
Use
a
rag
to
soak
up
any
spills
.

2
.
Install
pressure
gauge
in
place
of
switch
.

3
.
With
gauge
instalied,
start
engine
and
allow
to
reach

operating
temperature
.
Check
oil
pressureboth
cold

and
hot
.

NOTE-

For
the
most
accurate
test
results,
the
engine
oil
(and
filter)
shouldbe
newand
of
the
correct
grade
.

Oil
Pressure

"
¡dle
(mínimum)
..
.
.
..............
.
.
0
.5
bar
(7psi)

"
Regulated
pressure
(elevated
engine
speed)

4-cylinder
engines
..
......
4
.3
±
0
.2
bar
(63
t3
psi)

6-cylinder
engines
.
.
.............
.
4
.0
bar
(59
psi)

4
.
Remove
pressure
gauge
and
reinstall
pressure
switch
.

If
testing
shows
low
oil
pressure,
one
or
more
of
the
follow-

ing
conditions
may
be
indicated
:
OIL
PAN

"
Worn
or
faulty
oii
pump
.

"
Worn
or
faulty
engine
bearings



The
oil
pancan
be
removed
with
the
engine
instalied,
al-

Severe
engine
wear
.



though
specíal
enginesupport
equipment
will
be
needed
.

Al¡
of
these
conditionsindicate
the
need
for
major
repairs
.

Oil
pressure
warning
system,
testing

When
the
ignition
is
tumed
ora,
the
oil
pressure
warning
light

comes
ora
.
When
the
engine
ís
started
and
the
oil
pressure
ris-

es
slightly,
the
oil
pressure
switch
opens
and
thewarning
light

goes
out
.
Make
sure
the
oil
leve¡
is
correct
before
making

tests
.

1
.
Turra
ignition
switch
ora
.

"
Warning
light
ora
instrument
panel
must
light
up
.

2
.
Remove
connector
from
oil
pressure
switch
.

"
Warning
light
ora
instrument
panel
must
go
out
.

OIL
PAN

3
.
If
warning
light
does
not
light
when
ignition
is
ora,
re-

move
connector
from
oil
pressure
switch
anduse
a

jumper
wire
to
ground
connector
terminal
to
a
clean

metal
surface
.

NOTE
-

If
the
warning
light
comes
ora,
check
the
switch
as
de-
scríbed
in
the
nextstep
.
If
the
warning
light
does
not
come
ora,
thewiring
to
the
instrument
cluster
or
to
the

light
itself
isfaulty
.

4
.
To
test
switch,
connect
ara
ohmmeter
between
terminal

in
switch
body
and
ground
.
With
engine
off,
these

should
be
continuity
.
With
engine
running,
oil
pressure

should
opera
switch
and
there
should
beno
continuity

Replace
a
faulty
switch
.

WARNING
-

Keep
in
mind
that
low
oil
pressure
may
be
prevent-

ing
the
switch
from
tuming
the
light
out
.
If
the
light

remains
ora
while
the
engine
is
running,
check
the

oil
pressure
asdescribed
earlier
.
Do
not
drive
the
car
until
the
problem
is
corrected
.
Theengine
may
be
severely
damaged
.

Oil
pan,
removing
and
installing

(4-cylinder
engines)

1
.
Raise
car
arad
place
securely
ora
jackstands
.

2
.
Remove
splash
shíeld(s)
from
under
engine,
where
ap-

plicable
.

3
.
Drain
engine
oil
as
described
in
020
Maintenance
Pro-
gram
.

4
.
Disconnect
vacuum
hose
adapter
from
vacuum
brake

booster
at
rear
of
engine
compartment
.

5
.
Remove
oil
dipstick
guide
tube
mounting
nut
and
pull
guide
tube
from
oil
pan
.
See
Fig
.
2
.

GENERAL
.
........
.
...........
.
.
.
.
.
.
.
120-1



Camshaft
Position
(CMP)
Sensor
....
.
.
.
...
120-6

Disabling
Ignition
System
.
.
.
.
.....
.
.
.
.
.
.
.
120-2



Camshaft
position
(CMP)
sensor,
replacing

Warnings
and
Cautions
.
.
.
.
.
.
.....
.
.
.
.
.
.
.
120-2



(4-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
120-6

Camshaft
position
(CMP)
sensor,
replacing

IGNITION
SYSTEM
DIAGNOSTICS
.
.
.
.
.
.
120-3



(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
120-7
Basic
Troubleshooting
Principles
...
.
.
.
.
.
.
.
120-3



Knock
sensors,
replacing
.
.
...
.
.
.
.
.
.
.
.
.
.
.
.
120-7

Ignition
Firing
Order
.....
.
...
.
.
.
.....
.
.
.
.120-7

IGNITION
SYSTEM
SERVICE
.
.........
.
120-3

Checking
for
Spark
..
.
.
.
.
.
.
.
.
.
.......
.
.
.
120-3

Ignition
coil,
testing
and
replacing

(4-cylinder
engine)
.
.
.
.
.
.
.
.
.
.
.........
.
120-3

Ignition
coil,
testing
and
replacing

(6-cylinder
engine)
.........
.
..........
120-4

Crankshaft
Positionlrpm
Sensor
.......
.
...
120-5

Crankshaft
position/rpm
sensor,
testing
and

replacing
(front
mounted)
.........
.
.
.
.
.
.
120-6

Crankshaft
position/rpm
sensor,replacing

(rear
mounted)
.....
.
.....
.
.....
.
.
.
.
.
.
120-6

GENERAL



Troubleshooting
and
testing
of
the
engine
management

system
should
be
carried
out
using
the
BMW
specialized
ser

This
repair
group
covers
repair
andcomponent
replace-



vice
tester
(scan
tool)
.

ment
information
for
the
ignition
system
.
All
engines
use
a
distributorless
ignition
system
with
indívid-

ual
ignitioncoils
for
each
cylinder
.
There
is
no
distributor
cap

NOTE-



or
ignition
rotor
.
Each
coil
can
be
selectively
controlled
by
the

"
Spark
plug
replacement
is
covered
in
020
Mainte-



engine
control
module
on
a
cylinder-by-cylinder
basis
.
On
later

nance
Program
.



systems,
knock
sensors
are
used
to
monitor
and
control
igni-

"
For
fuel
related
troubleshooting
and
testing,
see
130



tion
knock
(ping)
and
adjusttiming
accordingly
.

Fuel
lnjection
.
Ignition
timing
is
electronically
controlled
and
not
adjust-

All
engines
covered
by
this
manual
use
an
advanced
en-



able
.
The
engine
control
module
(ECM)
usesengine
load,
en-

gine
management
system
.
The
engine
management
system



gine
speed,
coolant
temperature,
and
intake
air
temperature

incorporates
on-board
diagnostics,
fuel
injection,
ignition
and



as
the
basic
inputs
for
timing
control
.
Knock
detection
is
also

other
advanced
engine
control
functions
.



an
input
to
the
control
module,
where
applicable
.

Table
a
.
Engine
Management
System
Variants

Engine
code



1
System

4-cylinder
M42
(1.8
I)



Bosch
DME
Ml
.7
M44
(1
.9
I)



Bosch
DME
M5
.2
(OBD
II)

6-cylinder
M50
1992
(2.5
I)



Bosch
DME
M8
.1
1993-1995
(2
.5
I)



Bosch
DME
M33
.1
M52
1996-1998
(2.8
I)



Siemens
MS
41
.1
(OBD
II)

1998
(2
.5
I)



Siemens
MS
41
.1
(013D
11)
S50US
(3.0
I)



Bosch
DME
M3
.3.1
S52US
(3.2
I)



Siemens
MS
41
.1
(OBD
II)

120
Ignition
System

IGNITION
SYSTEM



120-1

IGNITION
SYSTEM
SCHEMATICS
...
.
.
.
.120-7

TABLES

a
.
Engine
Management
System
Variants
......
120-1

b
.
Ignition
Coil
Resistance
(M42
engine)
......
120-4

c
.
Ignition
Coil
Resistance
(M44
engine)
......
120-4

d
.
Ignition
Coil
Resistance

(6-cylinder
engine)
..
.
.
.
.
.
.
.
.
.
.
.
.....
.
..
120-5

NOTE-

All
engines
coveredby
this
manual,
with
theexception

of
the
1992
M50,
incorporate
knocksensors
as
part
of

the
engine
management
system
.

The
initial
ignition
point
is
determined
by
the
crankshaft
po-

sition/rpm
sensor
during
cranking
.
Once
the
engine
is
run-

ning,
timing
is
continually
adjusted
based
on
operating

conditions
.
A
characteristic
ignition
map
is
shown
in
Fig
.
1
.
A

map
similar
to
the
one
shown
is
digitally
stored
in
the
engine

control
module
.

GENERAL

121-
4



BATTERY,
STARTER,
ALTERNATOR

BatteryOpen-Circuit
Voltage
Test



Battery
Charging

Before
making
the
test,
load
the
battery
with
15
amperes
for



Discharged
batteries
can
be
recharged
using
a
battery

one
minute
with
a
batteryload-tester
or
turn
on
the
headlights



charger
.
The
battery
should
be
removed
from
the
luggage

for
about
one
minute
without
the
engine
running
.Then
discon-



compartment
during
charging
.

nect
the
battery
negative
(-)
cable
and
connect
a
digital
volt-

meter
acrossthe
battery
terminals
.
Open-circuit
voltage



Prolonged
charging
causes
electrolyte
evaporation
to
a
lev

levels
are
given
in
Table
c
.



el
that
can
damage
the
battery
.
Itis
bestto
use
a
low-current

charger
(6
amperes
or
less)
to
prevent
battery
damage

If
the
open-circuit
voltage
ís
OK
butthe
battery
still
lacks



caused
by
overheating
.

power
for
starting,
make
a
load
voltage
test
.
If
the
open-circuit

voltage
is
below
12
.4
volts,
recharge
the
battery
and
retest
.



WARNING
-

Hydrogen
gas
given
off
by
the
battery
duringcharg-

Table
c
.
Open-Circuit
Voltage
and
Battery
Charge



ing
is
explosive
.
Do
not
smoke
.
Keep
open
llames

away
from
the
top
of
the
battery,
and
prevent
elec
Open-circuit
voltage



State
of
charge



trical
sparks
by
turning
offthe
battery
charger
be-

12
.6
V
or
more



Fully
charged



fore
connecting
or
disconnecting
it
.

12
.4
V



1



75%
charged

12
.2
V



50%
charged



CAUTION-

12
.0
V



25%
charged



"
Battery
electrolyte
(sulfuric
acid)
can
damage
the
car
.
If
electrolyte
isspilled,
clean
the
area
11
.7
V
or
less



Fully
discharged



with
a
solution
of
baking
soda
and
water
.

Battery
Load
Voltage
Test

A
battery
load
tester
is
required
for
a
load
voltage
test
.
The



-
Always
disconnect
both
battery
cables
and
re-

test
is
made
by
applying
a
high
resistive
load
to
the
battery
ter-



move
battery
from
vehicle
during
battery
charg-
ing
.
Do
not
exceed
16
.5volts
at
the
battery
.
minals
and
then
measuring
battery
voltage
.
The
battery
should

be
fully
charged
for
the
most
accurate
results
.
The
battery
ca-

bles
mustbe
disconnected
before
making
the
test
.
If
the
volt-



ALTERNATOR
$ERVICE
age
is
below
that
listed
in
Table
d,
the
battery
should
be

replaced
.

WARNING
-

Always
wear
protective
goggles
and
clothing
when
performing
aload
test
.

Table
d
.
Battery
Load
Test-Minimum
Voltage

(apply
200
amp
load
for
15
seconds)

Ambient
temperature



Voltage

80°F
(27°C)



9
.6
V

60°F
(16°C)



9
.5
V

40°F
(4°C)



9
.3
V

20°F
(-7°C)



8
.9
V

0°F
(-18°C)



8
.5
V

ALTERNATOR
SERVICE

"
Always
allow
a
frozen
battery
to
thaw
before
at-
tempting
to
recharge
it
.

Before
checking
the
alternator
and
regulator,
make
sure
the

battery
is
fully
charged
and
capable
of
holding
acharge
.
Check
that
the
battery
terminals
are
clean
and
tight
and
the
al-

ternator
drive
belt
is
properly
tensioned
and
not
severely

worn
.

Charging
system,
checking

CAUTION-

Do
not
disconnect
the
battery
while
the
engine
is
running,
.
Damage
to
the
alternator
andlorengine
electronic
systems
may
result
.

1.
Turn
ignition
key
on
.
Check
that
the
chargewarning

lamp
comes
on
.

NOTE-

If
the
warning
light
does
not
come
on,
repair
any
wiring
or
bulb
faults
before
continuing
to
check
the
charging
system
.

GENERAL
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
.........
130-2



Intake
air
temperature
(IAT)
sensor,

Principles
of
Operatinn
.
.
.
.
.
.
.
.
.
.........
130-2



testing
and
replacing
...
.
...
.
.
.
.......
.
130-19

Basic
Engine
Settings
.
.
.
.
.
.
.
.
.
.
.
.
.
.
...
:
.
130-3



Throttle
position
sensor
(TPS),

DISA
(Dual
Resonance
Intake
System)
.
.
.
.
.
130-3



testing
and
replacing
...
.
...
.
.
.
.
.
...
.
.
.130-19

On-Board
Diagnostics
(OBD)



Idle
speed
control
valve,
testing
.
.
.
.
.
.
.
.
.
.
130-20

and
Fault
Diagnosis
.
.
....
.
......
.
.
.
...
130-4



Idle
speed
control
valve,
replacing
.
.
.
.
.
.
..
130-21

SecondaryAir
Injection
.
.
.....
.
.........
.
130-5



BOSCH
DME
M5
.2
COMPONENT
Warnings
and
Cautions
.
.
...
.
.
.
.........
.
130-6



REPLACEMENT
.....
.
......
.
....
.
.
.
..
130-21

ELECTRICAL
CHECKSAND



Mass
air
flow
sensor,
replacing
.
.
....
.
....
130-22

COMPONENT
TESTING
.
.
.
.
.
.
.
.
...
.
.
.
.
.
130-7



Engine
coolant
temperature
(ECT)

Main



sensor,
replacing
..
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-22
rela
y
testing



130
-7
,...
.
.
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.



Intake
air
temperature
(IAT)
sensor,
Fuel
pump
relay,
testing
.
.
.
.
.
.
.
...
.
.
.
.
.
.
.
130-7



rep
lacin
.
.
.
.
.
.
.
.
.
.
.g



.
.
.
.
.
.
.
...
.
.
.
..
.130-22
Oxygen
sensor,
testing
(Boschsystems
only)
130-8



Throttle
poson
sensor
(TPS)
replacing



13022
,



..
.-

FUEL
DELIVERY
TESTS
...
.
....
.
.
.
...
.
130-9



Idle
speed
control
valve,
replacing
...
.
....
.130-23

Operating
fuel
pump
for
tests
.
.
.......
.
...
130-9



SIEMENS
MS
41
.1
COMPONENT
Relieving
fuel
pressure
and



REPLACEMENT
.
...
.
.
.
.
.
.......
.
....
.130-23
connecting
fuel
pressure
gauge
......
.
..
130-10

Residual
fuel
pressure,
testing
.
.....
.
.
.
.
.
130-10



Mass
air
flow
sensor,
replacing
.
.......
.
.
.130-25

Fuel
pressure
regulator
response



Engine
coolant
temperature
(ECT)

to
engine
load,
testing
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
130-11



sensor,
replacing
.....
.
.
.
.
.
.........
.130-25

Fuel
rail
and
injectors,
checking
...
.
.
.
.
.
.
.
130-11



Intake
air
temperature
(IAT)
sensor,
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
.......
.
.
.130-25
Fuel
rail
and
injectors,
replacing



..
.
.
.
.
.
.
.
130-12



Throttleposition
sensor
(TPS),
replacing
.
.
.
130-26
Fuel
PressureRegulator
.........
.
.
.
.
.
.
.
130-13



Idle
s
eed
control
valve,
re
lacin



130-26
Fuel
pressure
regulatorreplacing



p



p



g
.'''...
.
'
,

(fuel
rail
mount)
...
.
.
.
.
.
.............
130-13



ECM
PIN
ASSIGNMENTS
.............
.
.
130-26
Fuel
pressure
regulator,
replacing



Engine
control
module
(ECM),
accessing
...
130-26
(undercar
mount)
.
.
.
.
.
.
.
.
.........
.
.
130-14

BOSCH
DME
M1
.7
COMPONENT

TESTS
AND
REPAIRS
.
.
.
.
.
...
.
.
.
.
.
.
.
.
130-14

Air
flow
sensor,
testing
and
replacing
.
.
.
.
.
.
130-14

Engine
coolant
temperature
(ECT)

sensor,
testing
and
replacing
...
.
.
.
.
.
.
.
.
130-15

Throttle
position
sensor
(TPS),

testing
and
replacing
.
..........
.
.....
130-16

Idle
speed
control
valve,
testing
and
replacing
.
.
.
.
.
............
130-16

BOSCH
DME
M3
.1
AND
M33
.1

COMPONENT
TESTS
AND
REPAIRS
.
.
.
130-17

Mass
Air
Flow
Sensor
.
.
.
.
.
.
.
.
.....
.
.
.
.
.130-17

Mass
air
flow
sensor
(hotwire),testing
and
replacing
.
.
.
.
.
.....
.
.
.
.
.
.
.
130-17

Mass
air
flow
sensor
(hot
film),

testíng
and
replacing
.
.
.
.....
.
.
.
.
.
.
.
.
.
130-18
Engine
coolant
temperature
(ECT)

sensor,
testing
and
replacing
..
.
.
.
.
.
...
.
130-18

130
Fuel
i
n
jection

FUEL
INJECTION



130-1

TABLES
a
.
Engine
Management
System
Variants
.........
.130-2
b
.
Mass
Air
Flow
Sensor
Variants
..
.
..
..........
.130-2
c
.
Fuel
Pressure
Specifications
..
.
.
...
..........
130-11
d
.
Engine
Coolant
Temperature
Sensor
or
Intake
Air
Temperature
Sensor
Test
Values
(DME
1
.7)
...
.
130-15
e
.
ThrottlePosition
Sensor
Tests
(DME
1
.7)
......
.130-16
f
.



Engine
Coolant
Temperature
Sensor
or
Intake
Air

Temperature
Sensor
Test
Values
(DME
3
.1/3
.3
.1)130-19
g
.
Throttle
Position
Sensor
Tests
(DME
3
.1/3.3
.1)
.
.130-20
h
.
ECM
Pin
Assignment-Bosch
DME
M1
.7
....
.
..
.130-28
i.



ECM
Pin
Assignment-Bosch
DME
M3
.1
.......
.130-30
j
.



ECM
Pin
Assignment-Bosch
DME
M3
.3
.1
.....
.130-32
k
.
ECM
Pin
Assignment-Bosch
DME
M5
.2
.......
.
130-34
I.



ECM
Pin
Assignment-Siemens
DME
MS
41
.1
..
.
130-36